/Engine/Source/Runtime/Engine/Classes/Kismet/KismetArrayLibrary.h
Finds the index of the first instance of the item within the array
The index the item was found at, or -1 if not found
static int32 Array_Find ( const [TArray](API\Runtime\Core\Containers\TArray)< int32 > & TargetArray, const int32 & ItemToFind )